Normalising particle-distribution biases using jet injection

Abstract

The distribution of particles in a jet with an initial bias is assessed using planar nephelometry, which is a planar imaging technique using Mie-scattering. In this study, a two-phase jet flow with a controlled initial bias is generated and various strategies are explored to correct this bias. The investigation compares the usefulness of injecting air at high momentum ratio under swirl or radial configurations. Radial injection of momentum is found to be superior to injection of swirl, consistent with swirl being a magnifier of eccentricities of a flow. Radial injection upstream from the nozzle can achieve a renormalised flow to develop prior to the exit, but may also lead to downstream biases in particle distribution for some conditions. Swirl injection inside the nozzle can modify the initial particle distribution, but will also have an enduring effect on the emerging near- and far-field flow.